[PATCH v2] i2c: sun6i-p2wi: Fix device node reference leak in p2wi_probe

[Uday Khare <udaykhare77@gmail.com>]

In p2wi_probe(), the device node reference obtained via
of_get_next_available_child() is stored in childnp. This reference is
never released, causing a device node reference leak.

Fix this by declaring childnp with the __free(device_node) cleanup
attribute, which automatically releases the device node reference
when childnp goes out of scope.

Fixes: 3e833490fae5 ("i2c: sunxi: add P2WI (Push/Pull 2 Wire Interface) controller support")
Signed-off-by: Uday Khare <udaykhare77@gmail.com>
---
v2:
- Use __free(device_node) and include <linux/cleanup.h> to automate the device
  node reference cleanup instead of manually calling of_node_put() on error and
  success paths (suggested by Chen-Yu Tsai).

 drivers/i2c/busses/i2c-sun6i-p2wi.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-sun6i-p2wi.c b/drivers/i2c/busses/i2c-sun6i-p2wi.c
index dffbe776a195..8469a0ea98d7 100644
--- a/drivers/i2c/busses/i2c-sun6i-p2wi.c
+++ b/drivers/i2c/busses/i2c-sun6i-p2wi.c
@@ -21,6 +21,7 @@
  * PMIC).
  *
  */
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/i2c.h>
 #include <linux/io.h>
@@ -184,7 +185,6 @@ static int p2wi_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
-	struct device_node *childnp;
 	unsigned long parent_clk_freq;
 	u32 clk_freq = I2C_MAX_STANDARD_MODE_FREQ;
 	struct p2wi *p2wi;
@@ -217,7 +217,9 @@ static int p2wi_probe(struct platform_device *pdev)
 	 * In this case the target_addr is set to -1 and won't be checked when
 	 * launching a P2WI transfer.
 	 */
-	childnp = of_get_next_available_child(np, NULL);
+	struct device_node *childnp __free(device_node) =
+		of_get_next_available_child(np, NULL);
+
 	if (childnp) {
 		ret = of_property_read_u32(childnp, "reg", &target_addr);
 		if (ret)
-- 
2.54.0